Get the Part After a Character in a String in JavaScript or Node.js

JavaScript comes with handy string methods. It provides useful basics to interact with strings. The standard library has some missing pieces which you can fill yourself by composing helpful utility methods.

One of these utilities is a function retrieve the part after a given character in a JavaScript string. This tutorial shows you how to approach it!

Node.js Series Overview

  1. String Replace All Appearances
  2. Remove All Whitespace From a String in JavaScript
  3. Generate a Random ID or String in Node.js or JavaScript
  4. Remove Extra Spaces From a String in JavaScript or Node.js
  5. Remove Numbers From a String in JavaScript or Node.js
  6. Get the Part Before a Character in a String in JavaScript or Node.js
  7. Get the Part After a Character in a String in JavaScript or Node.js
  8. How to Check if a Value is a String in JavaScript or Node.js
  9. Check If a String Includes All Strings in JavaScript/Node.js/TypeScript
  10. Check if a Value is a String in JavaScript and Node.js
  11. Limit and Truncate a String to a Given Length in JavaScript and Node.js
  12. Split a String into a List of Characters in JavaScript and Node.js
  13. How to Generage a UUID in Node.js
  14. Reverse a String in JavaScript or Node.js
  15. Split a String into a List of Lines in JavaScript or Node.js
  16. Split a String into a List of Words in JavaScript or Node.js
  17. Detect if a String is in camelCase Format in Javascript or Node.js
  18. Check If a String Is in Lowercase in JavaScript or Node.js
  19. Check If a String is in Uppercase in JavaScript or Node.js
  20. Get the Part After First Occurrence in a String in JavaScript or Node.js
  21. Get the Part Before First Occurrence in a String in JavaScript or Node.js
  22. Get the Part Before Last Occurrence in a String in JavaScript or Node.js
  23. Get the Part After Last Occurrence in a String in JavaScript or Node.js
  24. How to Count Words in a File
  25. How to Shuffle the Characters of a String in JavaScript or Node.js
  26. Append Characters or Words to a String in JavaScript or Node.js
  27. Check if a String is Empty in JavaScript or Node.js
  28. Ensure a String Ends with a Given Character in JavaScript or Node.js
  29. Left-Trim Characters Off a String in JavaScript or Node.js
  30. Right-Trim Characters Off a String in JavaScript or Node.js
  31. Lowercase the First Character of a String in JavaScript or Node.js
  32. Uppercase the First Character of a String in JavaScript or Node.js
  33. Prepend Characters or Words to a String in JavaScript or Node.js
  34. Check if a String is a Number
  35. Convert a String to Buffer
  36. Prevent Line Breaks in String Template Literals
  37. How to Implement a Custom `toString` Method (Coming soon)
  38. What Is `Symbol.toStringTag` and How to Use It (Coming soon)

Retrieve the Part After a Character in a String

Let’s create a strAfter helper function returning the part of a string after a given delimiter.

A way to approach this is to split a given string at each occurrence of the delimiter. This results in an array containing all the matches. From here, remove the first match and rejoin the remaining matches with the delimiter to return everything of the string after the first occurrence of the delimiter:

function strAfter (string, delimiter) {  
  if (delimiter === '') {
    return string
  }

  const substrings = string.split(delimiter)

  return substrings.length === 1
    ? string // delimiter is not part of the string
    : substrings.slice(1).join(delimiter)
}


// Using strAfter

const range = 'A1:L200'  
const end = strAfter(range, ':')  
// L200


const slug = '2020-this-is-a-tutorial-slug')  
const scrambledSlug = strAfter(slug, '-')  
// 'this-is-a-tutorial-slug'

The check if the given delimiter is empty is important. JavaScript splits a given string value at each character when using an empty string as the delimiter. Ensure you’re actually splitting a string at a valid delimiter.

The implementation of strAfter returns the full, original string in case the delimiter is not found. If you want another behavior in this situation, you should adjust the implementation :)

Use a Package

I’m the maintainer of the @supercharge/strings package providing convenient string utilities.

The package provides a fluent interface to interact with strings. One of the available methods is .after(delimiter) returning the part of the string after the first occurrence of the given delimiter:

const Str = require('@supercharge/strings')

Str('A1:L200').after(':').get()  
// 'L200'

Str('2020-this-is-a-tutorial-slug').after('-').get()  
// 'this-is-a-tutorial-slug'

Enjoy!


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